The present invention generally relates to headlights for vehicles
More particularly, it relates to a headlight for a vehicle, in particular a motor vehicle, which has a light module with at least one reflector, a light source and an optional projection optical system, wherein at least a part of the light module is connected with a first frame. The first frame is swivable about a first swivelling axis by a first adjusting means supported in a second frame, wherein the second frame is swivable by a second adjusting means about a second swivelling axis supported in a body-fixed frame carrier. The swiveling axes are arranged perpendicular to one another in one plane, and at least one of the frames is adjustable by a base adjusting means around an adjusting axis.
Headlights to be used in vehicles have in conventional constructions, a light source, a reflector and a cover member with or without a dispersion optical system. The headlights of this type have a disadvantage that the reflectors require a relatively significant space to provide a satisfactory quality or brightness of the low beam. From design and flow-technique reasons, it is however desired to reduce the mounting space required for a headlight. This can be achieved for example by the use of so-called PES (poly-ellipsoid system). PES-headlights have a low beam optical system which projects the light produced by the light source and reflected by the reflector onto the roadway in front of the vehicle. With the PES system the mounting space occupied by the headlight is significantly reduced when compared with conventional headlights.
It is known to arrange headlights or parts of the headlight of the vehicle (the light module) movable relative to the vehicle body, for turning the headlight or parts of the headlight. For example the headlight or parts of the headlight can be turned about a horizontal swiveling axis to adjust the light range in the vertical direction. In Europe all new vehicles which are produced since Jan. 1, 1999 must have a light range regulation or a manually operated light range adjustment.
It is further known to arrange headlights or parts of the headlights swivelable about a second additional swiveling axis. For example the second swiveling axis can be arranged vertically to turn the light outlet direction of the headlight in a horizontal direction. With sufficiently large swiveling angles for example up to +/xe2x88x9215xc2x0, it is possible to execute a curve light operation. Thereby the light outlet direction of a headlight can be adjusted to a radius of a curve over which a vehicle is driving, to obtain an optimal illumination of the roadway, in particular over curves with a small curve radius.
It is known to support a headlight or parts of the headlights by cardans which simultaneously allow both a light range regulation and also a curved light operation. It is in particular known to design the cardan bearing so that at least a part of the headlight is connected with a first frame which is supported swivelably in a second frame, which is also supported swivelably in a body-fixed frame carrier.
It has been recognized that it is advantageous when the swiveling axes intersect in one point, and the intersection point of the axes from dynamic reasons can not be arranged in the vicinity of a center of gravity of headlight parts to be supported. By swiveling of the headlight parts around two intersecting axes the dimensions of gaps which occur between the movable parts of the headlight and the body-fixed parts which adjoin the movable headlight parts can be reduced. Such a headlight is disclosed for example in the pending and not published patent document DE 101 29 968.
For compensation of manufacturing tolerances, it is necessary to bring the headlight or the headlight parts at the end of the complete mounting of the vehicle to a base adjustment, in particular to satisfy the adjusting requirements which are prescribed in accordance with corresponding regulations. For this purpose base adjustment means are provided, with which the headlight or parts of the headlight are adjustable around an adjusting axis. The base adjusting means which are used for this purpose include adjusting screws which are for example in toothed engagement with the headlight or parts of the headlight via transmission elements.
It has been determined that in known headlights it is disadvantageous that the base adjustment of the headlight is possible only with a relatively large, disturbing gaps between vehicle-fixed and movable headlight parts.
Accordingly, it is an object of the present invention to provide a headlight of the above mentioned general type, which avoids the disadvantages of the prior art.
More particularly, it is an object of the present invention to provide a headlight which can be operate with a curve light function and a light range regulation, wherein an independent base adjustment of the headlight is possible with lowest possible curve dimensions between movable and vehicle-fixed parts of the headlight.
In order to achieve these objects, the adjusting axis is arranged so that it is aligned with one of the swiveling axes.
Since the adjusting axis is aligned with one of the swiveling axes, small gap dimension between movable and vehicle-fixed parts of the headlight is obtained with the cardanic suspension of the headlight or the headlight parts, without increasing the gap dimension for allowing the base adjustment.
With the proposed arrangement, the movable headlight parts are arranged so that their outer surfaces which are spaced the farthest from the intersection point of the swiveling axes, during their turning describe the surface of a sphere. The vehicle-fixed headlight parts adjoining the movable parts of the headlight, for example optical screens, can be arranged so that they directly adjoin a remaining minimum gap. With the spherical movement of the headlight parts, a gap formed by the distance between the movable and vehicle-fixed headlight parts remains constant. This is especially advantageous when for carrying out a curve light operation relatively great swiveling angle of +/xe2x88x9215xc2x0 is required.
In accordance with a further embodiment of the present invention, the first and the second frames are adjustable correspondingly through base adjusting means around corresponding adjustment axes. The adjusting axes are arranged in alignment with the turning axes.
This arrangement guarantees that a base adjustment of the vehicle headlight can not be performed in horizontal and vertical directions without a large gap dimension between movable and vehicle-fixed headlight parts. For example a first frame is provided, on which the movable parts of the headlights, for example a light source, a reflector and/or a projection optical system are mounted. This first frame is horizontally swivelable about a first, vertical swiveling axis by means of a first adjusting means. Thereby a curve light operation can be executed. This first frame is arranged in a second frame which surrounds the first frame, which is swivelable about a second, horizontal swiveling axis by means of a second adjusting means. Thereby a light range regulation is possible. The second frame is supported in a body-fixed frame carrier.
In order to provide the base adjustment of the first and the second frames, the base adjustment means are provided. They are arranged in accordance with the present invention so that the adjusting axes around which the frames can swivel for their base adjustment are in alignment with the swiveling axes for swiveling the frames for executing the curve light function or the light range regulation. This arrangement allows to reduce the gap it between the movable and vehicle-fixed headlight parts to a minimum value.
In accordance with another embodiment of the invention, it is provided that base adjustment means operate between the frame carrier and the first frame and/or between the frame carrier and the second frame, and the base adjustment means adjusts the relative position of the first adjusting means to the first frame and/or the relative position of the second adjusting means to the second frame. The base adjustment means are arranged so that a swiveling of the first and second frames is not performed as in conventional systems by a direct action of the base adjustment means on the frames, but instead with interposition of the adjusting means. The base adjustment means provide the position and orientation of the adjustment means which thereby assume a predetermined relative position relative to the first and the second frames.
Advantageously the adjusting means each have an adjustment means drive and a stroke means connected with a frame through a hinge. The adjusting means drive can be activated for example pneumatically, hydraulically or electrically and stroke means can be formed as pistons. Such adjusting means and stroke means are advantageous and known from a plurality of industrial applications.
In accordance with a further embodiment of the present invention, the base adjustment means have correspondingly a base adjustment drive with a coupled first transmission member which is swivelable about a frame carrier-fixed axis. This first transmission member can support an adjustment means drive, wherein by swivelling the first transmission member a frame-fixed axis of this adjustment means drive is swivelable also to adjust the relative position between the adjusting means drive and one of the frames. For example, the first transmission member of the adjusting means drive carries the corresponding adjustment means, with which a frame is swivelable for light range regulation vertically about a horizontal swiveling axis.
In accordance with a further embodiment of the present invention, the first transmission member is coupled to a second transmission member, which carries an adjustment means drive and a first frame-fixed axis. For example via a base adjustment drive, a coupled first transmission member which is swivellable about a frame carrier-fixed axis can be swivelled. Thereby, a second transmission member which is coupled to the first transmission member is swivellable about a further axis, wherein the further axis is frame-fixed or in other words is arranged in one of the swivellable frames. These two transmission members can support as adjustment means drive, with which for example a frame is swivellable about a vertical swivelling axis in a horizontal direction. With the above described arrangement it is possible to swivel the second transmission member via the base adjustment drive and the first transmission member and thereby to adjust the adjusting means which is fixedly connected with the second transmission member, in its relative position relative to one of the frames.
Advantageously one of the two transmission members have a coulisse guide and the other transmission member has a pin which engages in the coulisse guide. Such a support provides a gap-free movement transmission in one plane. This movement transmission is required for bringing one of the two frames to its base position. With the special design and connection between the first and second transmission members by means of the coulisse guide and the engaging pin it is achieved that the second transmission member is kinematically coupled with respect to the first transmission member in a perpendicular plane for a gap-free movement transmission.
In accordance with the present invention the base adjustment drive and the first transmission member are connected with one another through a self-locking screw hinge. Thereby after finishing of the base adjustment, the base adjustment member and the first transmission member are retained in the selected position. Thereby also the base adjustment of a coupled frame is determined.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.